Self-replication in a test-tube!

Departments of Chemistry and Molecular Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.

Abstract:

An RNA enzyme that catalyzes the RNA-templated joining of RNA was converted to a format whereby two enzymes catalyze each other’s synthesis from a total of four oligonucleotide substrates. These cross-replicating RNA enzymes undergo self-sustained exponential amplification in the absence of proteins or other biological materials. Amplification occurs with a doubling time of about one hour, and can be continued indefinitely. Populations of various cross-replicating enzymes were constructed and allowed to compete for a common pool of substrates, during which recombinant replicators arose and grew to dominate the population. These replicating RNA enzymes can serve as an experimental model of a genetic system. Many such model systems could be constructed, allowing different selective outcomes to be related to the underlying properties of the genetic system.

A test tube based system of chemicals that exhibit life-like qualities such as indefinite self-replication, mutation, and survival of the fittest, has been created by US scientists. The researchers say their perpetually replicating RNA enzymes take us a step closer to understanding the origins of life on Earth, as well as to how life may one day be synthesised in the lab.

The system, created by Gerald Joyce and Tracey Lincoln at the Scripps research institute in La Jolla, California, involves a cross-replicating pair of ribozymes (RNA enzymes), each about 70 nucleotides long, which catalyse each other's synthesis. So the 'left' ribozyme templates the synthesis of the 'right', which in turn templates the 'left' and so on, building each other via Watson-Crick base pairing.